Hydraulic damper elastomeric body having alternating rigid and deformable wall sections

ABSTRACT

A sleeve bearing comprising two thrust-bearing parts wherein one thrust-bearing part surrounds the other. The two thrust-bearing parts extend essentially parallel to one axis and are braced against each other by a resilient member made of rubber elastic material. The resilient member defines at least one pair of fluid-filled chambers which are connected by at least one damping opening and are arranged so that they diametrically oppose one another. The chambers are bounded in the axial direction on both sides by end walls, which are elastically deformable in one partial area. Each end wall has a rigid zone which resists deformation. At one end of each fluid chamber, the rigid zone of the end wall extends to the inner thrust-bearing part, and at the other end of each fluid chamber, the rigid zone of the end wall extends to the outer thrust-bearing part.

BACKGROUND OF THE INVENTION

The present invention relates generally to a sleeve bearing comprisingtwo thrust-bearing parts, wherein one thrust-bearing part surrounds theother. The two thrust-bearing parts extend essentially parallel to oneaxis and are braced against each other by a resilient member made ofrubber elastic material. The resilient member defines at least one pairof fluid-filled chambers, wherein the chambers are connected by at leastone damping opening and are arranged so that they diametrically opposeone another. The chambers are bounded in the axial direction on bothsides by end walls, which are elastically deformable in one partialarea.

A sleeve bearing with hydraulic damping is disclosed by the EuropeanPatent Office application 0 009 120. It comprises a number of pairs offluid-filled chambers, wherein the chambers are arranged on mutuallyopposing sides of a plane through the axis of the bearing and one behindanother along the direction of the axis. The chambers are in fluidcommunication with one another through damping openings, which areindependent of one another. In this manner, vibrations which areintroduced at right angles to the axis and vibrations which areintroduced parallel to the axis are able to be damped effectively.However, manufacturing such a sleeve bearing entails a considerableexpenditure.

SUMMARY OF THE INVENTION

The object of the present invention is to further develop such a sleevebearing while achieving the goal of a simplified production.

This objective is solved according to the invention with a sleevebearing of the type mentioned at the outset wherein, next to thedeformable partial area, each end wall has a rigid zone which resistsdeformation. At one end of each fluid chamber, the rigid zone of the endwall extends to the inner thrust-bearing part, and at the other end ofeach fluid chamber, the rigid zone of the end wall extends to the outerthrust-bearing part. This configuration achieves good vibration dampingwith only one damping opening, both when vibrations are introducedparallel to the axis of the bearing, as well as when they are introducedat right angles to the axis of the bearing. The sleeve bearing can beproduced quite simply when the rigid zones are formed integrally withthe resilient member and the elastically deformable partial areas.

An advantageous embodiment of the present invention provides at leasttwo chamber pairs, whose chambers are arranged around the circumferenceof the bearing. This embodiment allows damping of vibrations in adirection parallel to the axis and in two axially normal directionswhich are perpendicular to one another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a sleeve bearing according to theinvention in longitudinal cross-section;

FIG. 2 shows a cross-sectional view of the sleeve bearing according toFIG. 1, taken along the line 2--2 in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The sleeve bearing shown in FIGS. 1 and 2 comprises an outerthrust-bearing part 1 and an inner thrust-bearing part 2. The outerthrust-bearing part 1 has a tubular design and surrounds the innerthrust-bearing part 2. The two thrust-bearing parts 1, 2 extendessentially parallel to an axis 10 and are braced against each other bya resilient member 3 made of an elastomeric material. The resilientmember 3 defines at least one pair of fluid-filled chambers 5, 6,wherein the chambers are connected by at least one damping opening 8 andare arranged on opposite sides of a plane through the axis 10 so thatthey diametrically oppose one another.

The chambers 5, 6 are bounded in the axial direction on both sides byend walls, which are each elastically deformable in one partial area 11,12, 13, 14. Next to each deformable partial area 11, 12, 13, 14, therespective end wall has a rigid zone 15, 16, 17, 18, which isessentially incapable of deformation. At one end of chamber 5, the rigidzone 15 extends to the outer thrust-bearing 1, and at the other end ofchamber 5, the rigid zone 16 extends to the inner thrust-bearing 2.Similarly, at one end of chamber 6, the rigid zone 17 extends to theinner thrust-bearing 2, and at the other end of chamber 6, the rigidzone 18 extends to the outer thrust-bearing 1.

The damping action achieved depends significantly on the relative extentof the rigid zones in the radial direction. However, an increasingextent in the radial direction may adversely affect the relative radialmobility of the thrust-bearing parts. Therefore, it is advantageous thatthe rigid zones of the ends walls of each chamber overlap one another inthe radial direction but leave some clearance between themselves and therespective thrust-bearing part. In a preferred embodiment of the presentinvention, each rigid zone covers between 50 to 75% of the availablespace between the inner and outer thrust-bearing parts.

In the illustrated embodiment, the end walls of the chambers 5, 6consist of rubber. Each is an integral part of the resilient member 3and is connected at its periphery to a metallic end-window tube 9. Thisend-window tube 9 serves to affix the end walls to the outerthrust-bearing part I in an immovable and fluid-tight manner. Thethrust-bearing parts 1, 2 in the illustrated embodiment consist of ametallic material.

During normal operational use, the chambers 5, 6 are filled with ahydraulic fluid, for example with a glycol and water mixture. They arein a reciprocal, hydraulic communication with one another through thedamping opening 8 which is dimensioned in such a way that when liquidcomponents are pressed through, a damping action results. The dampingopening 8 in the illustrated embodiment is surrounded by a separatemetallic ring, which is immovably affixed to the inner thrust-bearingpart 2. The damping opening is shown in the center of the bearing, butit can also be placed, as needed, at another location.

When vibrations are introduced perpendicularly to the axis 10, thevolume of each liquid-filled chamber 5, 6 of the sleeve bearingalternately increases and decreases. Consequently, the pressure in eachchamber 5, 6 alternately rises and drops. As a result, liquid componentsare pressed through the damping opening 8 into the chamber with thelower pressure, thus damping the exciting vibration.

In the case of the illustrated embodiment, damping is also achieved whenvibrations are introduced parallel to the axis 10. As with perpendicularvibrations, the volume in each liquid-filled chamber 5, 6 alternatelyincreases and decreases so that liquid components are pressed out of thechamber having a higher pressure into the chamber having a comparativelylower pressure. The resulting damping action corresponds to the onepreviously described.

In an alternative embodiment, damping may be achieved in more than onedirection perpendicular to the axis of the sleeve bearing by providingadditional pairs of chambers. The chambers of such a sleeve bearing lapover one another in the circumferential direction. Thus, for example, itis possible to use two pairs of chambers to damp vibrations which areintroduced in two axially normal directions which are perpendicular toone another.

It will be appreciated that the above description is set forth forillustration, and the scope of the present invention is not limited tothe described embodiments.

What is claimed is:
 1. A sleeve bearing comprising an outerthrust-bearing part and an inner thrust-bearing part, wherein the outerthrust-bearing part surrounds the inner thrust-bearing part and whereinthe two thrust-bearing parts extend essentially parallel to an axis andare braced against each other by a resilient member made of anelastomeric material, wherein the resilient member defines at least onepair of fluid-filled chambers, wherein the chambers are connected by atleast one damping opening and are arranged so that they diametricallyoppose one another, wherein each chamber is bounded in an axialdirection on each side by an end wall which is elastically deformable inone partial area, wherein each end wall comprises a rigid zone having astiffness greater than the elastically deformable partial area of theend wall, and wherein on one side of each fluid-filled chamber the rigidzone of the corresponding end wall extends to the outer thrust-bearingpart and on the other side of each fluid-filled chamber the rigid zoneof the corresponding end wall extends to the inner thrust-bearing part.2. The sleeve bearing according to claim 1, wherein the rigid zones ofthe end walls of each chamber overlap one another in the radialdirection.
 3. The sleeve bearing according to claim 2 wherein the rigidzones are integral parts of the resilient member.
 4. The sleeve bearingaccording to claim 3, wherein the rigid zones surround the dampingopening.
 5. The sleeve bearing according to claim 4, wherein at leasttwo chamber pairs are provided, whose chambers are arranged around acircumference of the bearing.
 6. The sleeve bearing according to claim3, wherein at least two chamber pairs are provided, whose chambers arearranged around a circumference of the bearing.
 7. The sleeve bearingaccording to claim 2, wherein the rigid zones surround the dampingopening.
 8. The sleeve bearing according to claim 7, wherein at leasttwo chamber pairs are provided, whose chambers are arranged around acircumference of the bearing.
 9. The sleeve bearing according to claim2, wherein at least two chamber pairs are provided, whose chambers arearranged around a circumference of the bearing.
 10. The sleeve bearingaccording to claim 1 wherein the rigid zones are integral parts of theresilient member.
 11. The sleeve bearing according to claim 10, whereinthe rigid zones surround the damping opening.
 12. The sleeve bearingaccording to claim 11, wherein at least two chamber pairs are provided,whose chambers are arranged around a circumference of the bearing. 13.The sleeve bearing according to claim 10, wherein at least two chamberpairs are provided, whose chambers are arranged around a circumferenceof the bearing.
 14. The sleeve bearing according to claim 1, wherein therigid zones surround the damping opening.
 15. The sleeve bearingaccording to claim 14, wherein at least two chamber pairs are provided,whose chambers are arranged around a circumference of the bearing. 16.The sleeve bearing according to claim 1, wherein at least two chamberpairs are provided, whose chambers are arranged around a circumferenceof the bearing.